The objectives of this joint program between SRI International and the University of California Medical Center at San Diego are to develop and evaluate an advanced ultrasonic instrument for the non-invasive detection and quantification ofatherosclerotic plaque in the major abdominal arteries. The instrument will provide a real-time, high-resolution B-modeimage of the abdominal aorta, iliacs, and mesentery arteries. The system will also be suited for diagnosis of occlusivedisease in the extremities.